Method of making galvanized ferrous pipe



July 19, 1938.

METHOD F. N. SPELLER:

Filed Sept. 1, 1936 OF MAKING GALVANIZED FERROUS PIPE IN VEN TOR.

FEfiNK' N. 5PEL LEE.

Patented Jul 19, 1938 UNITED STATES PATENT OFFICE 2,124,520 nm'rnon or MAKING csnvsmznn- FERBOU SPIPE Frank N. speller, Pittsburgh, Pa., assignor to National Jersey Tube Company, a corporation of New This invention relates to galvanized ferrous pipe, one of the objects being to increase the service life of such pipe.

According to the invention, ferrous pipe is gal-' vanized by the conventional hot-dip method excepting that the pipe is removed from the molten zinc in a horizontal position so as to retard the gravitational fiow of zinc from its surfaces, the pipe being continuously rotated during the solidification of the zinc on its surface andcontinuously maintained in a horizontal position until this solidification is completed. Preferably, the pipe is rotated at suflicient speed to assure a uniform distribution of the zinc over its surfaces but at an insuflicient speed to assure any material centrifugal eflect on this zinc. This procedure results in the pipe having relatively heavy layers of free zinc on its surfaces and in a uniform dis- 9 tribution of the zinc over its surfaces from end to end and on both its inside and outside.

It has been found that pure zinc provides much greater protection against corrosion than does the zinc and iron alloy which prevails at the junction between the zinc and .the ferrous pipe 25 it covers. By the above described procedure pipe is obtained having a much greater thickness of free zinc than can result when pipe is dipped by the usual methods.

A modification of the above may consist in 39 providing a suitable means for retaining a predetermined amount of molten zinc inside the pipe, and in then rotating this pipe .until solidification of the zinc is completed. This provides for a greater thickness of zinc on the inside of 35 the pipe than can otherwise be obtained and, at the same time, assures a uniform distribution of the zinc from end to end of the pipe.

In the drawing, Figure 1 is a top plan of suitable apparatus for rotating the pipe being coat- 40 ed; Figure 2 is a side elevation of the apparatus of Figure 1: Figure 3 shows how the zinc may be retained in the pipe after it has been'removed from the usual bath of molten zinc; and Figure 4 is a sectional view taken on the line 45 IV-IV of Figure 3.

The apparatus illustrated by Figures land 2 includes a zinc kettle l adapted to contain the molten zinc in which the pipe is dipped. A shaft I runs parallel one edge of this kettle and carries arms 8 adapted to lift the pipe horizentally out of the same, this shaft being rotated by a suitable device l. The arms I may be raised into alignment with declining skids 5 which lead to a series of spaced rollers 6 powered by a motor I and adapted to horizontally receive the pipe 5' between them and rotate the same.

In use, the pipe is placed in the zinc in the kettle i for a suitable length of time and is then removed by raising the arms I, this automatically starting the pipe to rotate due to the shape of 10 these arms. Upon removal from the zinc the pipe runs relatively slowly down the skids 5 and between the rollers 6.- Here the pipe is rotated until the zinc solidifies. The pipe is horizontal at all times and the zinc is not wiped from its 15 surfaces. 'lhe advantages of this procedure have already been described.

Figures 3 and 4 illustrate the pipe 8 as being provided with caps 9 which may be fixed to the ends of the pipe in any manner, as by a threaded engagement with the same, each of these caps being provided with a concentric opening it. Assuming the pipe to be fitted with these caps and handled by the apparatus illustrated by Figures 1 and 2 in the aforementioned manner, the pipe receives a thicker coating of zinc inside than it does outside. Obviously, the zinc is uniformly distributed from end to end of the pipe.

I claim:

1. A method of hot-dip galvanized ferrous pipe 3 including dipping the pipe in molten zinc, removing the pipe from the molten zinc in horizontal position and rotating said pipe while continuously maintaining it in a horizontal position during the solidification of zinc on its surfaces.

2. A method of hot-dip galvanizing ferrous pipe, including dipping the pipe in molten zinc, removing the pipe horizontally from the molten zinc while positively obstructing its ends to an extent sufficient to retain a greater quantity of zinc inside the pipe than if the ends were com- .4 pletely open and rotating the pipe during solidification of the zinc thus retained inside the pipe.

3. A method of hot-dip galvanizing ferrous pipe, including dipping the pipe in molten zinc, removing the pipe horizontally from the molten zinc and rotating the pipe during its removal from the zinc and thereafter until the zinc retained on the surfaces of the pipe is solidified.

' FRANK N. SPELLER.

CERTIFICATE OF CORRECTION Patent No. 2,12%520. w July 19, 195

FRANK N. SPELLER. I

It is hereby certified that error appears in the printed specification of the above number ed patent requiring correction as. follows: Page 1, second column, line 50, olaiml, for the word. "galvanized" read galvanizing; and that the said Letters Patent should'be readwith this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 50th day of August, A, D. 1958.

Henry Van Arsdale (Seal) Acting Commissioner 'of Patents. 

